Lightning arrester



A. L. ATHERTON LIGHTNING ARR-ESTER Oct. 1.4 1924.

Filed Jan. 24. 1921 *him S m WITNEssEs;

Patented Oct. 14, 1924.

UNITED STATES PATENT OFFICE.A

ALFRED Il. ATHERTON, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION 0F PENNSYL- VAN IA.

LIGHTNING ARRESTER.

Application filed January 24, 1921.

To all whom t may concern.'

Be it known that I, ALFRED L. ATHERTON, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Light ning Arresters, of which the following is a specification.

My invention relates to protective devices and it has particular relation to lightning arresters of the multiplesgap type that are enclosed in casings and adapted for outdoor service, the casings operating also, to protect or shield the active elements thereof from unauthorized and improper interferencey 'when in a charged condition.'

Heretofore, it has been customary to con struct the noirarcing conducting members in the form of knurled cylinders adapted to effect a point discharge between the respective members in the event of a surge 'of potential in the line. Should a device provided with conducting members of the above type be frequently subjected to the destructive effect of heavy discharges, the knurled surfaces of the members soon became so pitted or otherwise deformed'l as to necessitate the replacement thereof.

One 'of the objects of my invention is to provide a device of the above indicated character in which the conducting members comprise relatively inexpensive machine screws of standard sizes, yand preferably of a non-arcing metal, so arranged that the threaded body portions thereof perform the same function asthe knurled cylinders heretofore employed, thereby materially reducing the expense of repairs.

Another object of my invention is to so dispose or interleave the electrodes as to increase the cree-page distance therebetween.

Another obj ect of my invention is to provide a lightning arrester of the above indicated character that shall be simple in construction, economical in manufacture, and reliable in operation and one that shall be protected or shielded against inadvertent` or intentional interference by unauthorized persons and, at the same time, be so designed that the accessible parts thereof shall be thoroughly insulated from one another and the active elements adequately protected against all weather conditions.

Serial N0. 439,393.

Fig. 2 is a vertical longitudinal section t taken on line II-II of Fig. l, and illustrating the arrangement of the screw-threaded conducting members.

Fig. 3 is a vertical transverse sectional view taken on line III-III of Fig. 2.

Referring to the drawings, a lightning arrester embodying my invention is illustrated as comprising an outer casing .1, preferably constructed of insulating material, such as porcelain, for example, and consisting of a top 2,' end portions 3 and side walls 4 and being open at the bottom, as indicated at 5. The top or upper portion 2 of the casing l may be providedwiith a lug or extension 6 adapted to be secured to a pole, cross-arm or other suitable supporting structure.

An inner casing 7 is telescopically disposed within the casing 1 and comprises end walls 8, a single side wall 9, and a top and a bottom l0 and 1l, respectively. The casing 7 is open on one side, as indicated at 12, by means of which access may be readily had to the interior thereof. The casing 7' is inserted within the casing l through the opening 5 at the bottom thereof and, when in place, the open side 12 is closed by the side wall 4 of the outer casing 1. Suitable means, such as pins 13, may be provided to 7 from becomingaccprevent the casing dentally displaced.

It will be apparent. from thev foregoingy that the outer casing l tends to shed rain or protects i-t from the weather and prevents the same from leaking into the inner casing 7.

The conducting members preferably comprise a plurality of machine screws 14 of non-arcing material disposed in a vertical longitudinal plane and alternately mounted in the top and bottom walls l0 and 11 of the casing 7 to extend in opposite directions and in spaced and parallel relation with re spect to each other.

The heads of the screws 14 are so disposed within the recesses l5 as to lie flush with the outer surface of the inner casing 7. The screws are preferably retained in place by means of lock nuts 16 abutting against the inner surfaces of the walls 10 and 11, respectively.

A resilient contact member 17 is secured to one of the screws 14 and extends upwardly through an aperture 18 in the end wall 8 and yieldably engages a line terminal 19. The end wall 8 of the casing 7 is provided with a slot 2O within which the terminal 19 extends. The upper extremity oi-- the contact member 17 is formed with an inwardly inclined portion 21 which provides a cam surface for engagement with the ter minal 19 when the casing 7 is inserted into the casing 1.

The conducting element 14, at the opposi-te vend of the series, is connected, by means of a copper strip 22, to a spring clip or terminal 23 which is also mounted upon the bottom 11 of the inner casing 7. second spring clip 24, in alinement with the clip 23, is positioned adjacent to the other end of the casing 7 and is connected to the clip 23 by a resistance rod 25, of any suitable material having a high specific resistance.

The clip 24 is connected to a resilient contact member 26, similar in construction to the member 17, and ex-tends through an opening 27 in the end wall 8 for yieldable engagement with a ground terminal 29 which is mounted in the end wall 3 of the outer casing. The member 26 may also be provided with an inclined portion 30 adapted to engage the terminal 29 and be forced inwardly, when the inner casing 7 is disposed in place. A channel 31 may be provided in the Wall Bot the inner casing and within which the ground terminal may pro `ect. J It will be apparent that. the threaded body portions of lthe adjacent screws 14 eii'ect a point discharge between the respective electrodes in a manner similar to the knurled surfaces of the cylinders heretofo're employed and, at the same time, being relatively inexpensive and are readily interchangeable.

I claim as my invention:

1. An electrode for lightning` arresters having a threaded discharge surface.

2. A protective device comprising a plu rality ot spaced electrodes having threaded discharge surfaces.

3. A protective device having a plurality of electrodes arranged to form a spark gap and provided with screw-threaded portions adapted to eil'ect point discharges between said electrodes.

4. .A protective device comprising a plurality ot electrodes having threaded discharge surfaces arranged in spaced and parallel relation within a single plane.

5. A protective device comprising a plurality of electrodes having threaded discharge surfaces arranged in spaced and interleaved relation.

6. A protective device comprising a plurality oit electrodes having threaded discharge surfaces arranged in spaced and parallel relation and extending alternately in opposite directions with respect to each other.

7. A protective device comprising a plurality ot electrodes having threaded dis charge surfaces arranged in spaced and parallel relation, and alternately extending in opposite direct-ions in overlapped relation with respect to each other.

8. A protective device comprising an outer casing, an inner casing telescopially mounted in said outer casing, a plurality oit electrodes mounted in said inner casing, a resistance element connected in series with said electrodes, a plurality of terminals mounted in the walls of said outer casing and a plurality ot resilient contact members connected to said electrodes and to said re sistance element7 respectively, for yieldable engagement with said terminals.

1n testimony whereof, I have hereunto subscribedmy naine this 17th day of January 1921.

ALFRED L. ATHERTON. 

